Eihter one of the amps mentioned will easily out-perform the amps in the Denon. I wouldn't worry too much about the damping factor numbers, once you get past a factor of 100 or so it really doesn't make much difference.
I would consider the efficiency of the speakers and the sound pressure levels you wish to achieve as being more important specs. for you to consider.
As an example, I am driving my Gallo Reference 3.1 speakers (88 db efficiency) with a Butler TDB-5150 5-channel tube amp with 150 watts/channel (into 8 ohms, 225 watts into 4 ohms) and it gets *plenty* loud enough for me.
In fact, you may want to consider buying a Butler for your application, it will provide you with the sweetness of tubes coupled with the "balls" of a MOSFET amp:
http://butleraudio.com/tdb5150.php
Finally, you may want read this whitepaper about amplifier damping factors, it will dispel some common mis-conceptions that many folks have about it:
http://butleraudio.com/Damping1.php
Good luck!
-RW-
I would consider the efficiency of the speakers and the sound pressure levels you wish to achieve as being more important specs. for you to consider.
As an example, I am driving my Gallo Reference 3.1 speakers (88 db efficiency) with a Butler TDB-5150 5-channel tube amp with 150 watts/channel (into 8 ohms, 225 watts into 4 ohms) and it gets *plenty* loud enough for me.
In fact, you may want to consider buying a Butler for your application, it will provide you with the sweetness of tubes coupled with the "balls" of a MOSFET amp:
http://butleraudio.com/tdb5150.php
Finally, you may want read this whitepaper about amplifier damping factors, it will dispel some common mis-conceptions that many folks have about it:
http://butleraudio.com/Damping1.php
Good luck!
-RW-